1. Field of the Invention
The invention relates to a magnetic-tape recording and/or playback apparatus, in particular a cassette player or recorder, (hereinafter referred to simply as a tape recorder) comprising: a depressible play button, a command member which is connected to the depressible play button and which is movable thereby, a movable and spring-loaded latching member which cooperates with said command member in the depressed condition, a capstan, a flywheel which is coupled to the capstan and drivable by a motor, a tape stoppage detection device, which comprises a component which during tape stoppage performs a movement which is characteristic of said condition, and an automatic stop device for automatically switching off the apparatus when the tape transport stops, said stop device comprising a movable frame plate which during tape stoppage can be moved by the tape stoppage detection device, so that a cooperation is obtained between the flywheel and the latching member by means of a force transmitting member which cooperates with the latching member at a first end for releasing said member against the spring load.
2. Description of the Prior Art
Such a tape recorder is known from U.S. Pat. No. 3,754,695. Said known apparatus comprises a tape-stoppage detection device with a gear-wheel disposed on the capstan, which gear-wheel engages an idler wheel which is journalled on a lever for free rotation. The idler wheel drives a third gear-wheel, which is rigidly mounted on a spindle which is in contact with the pressure roller of the apparatus. The third wheel spindle is mounted in a bracket, which is rotatable about a spindle fastened to the lever on which the idler wheel is journalled for free rotation. The three gear-wheels all have the same dimensions, so that the spindle which is in contact with the pressure roller rotates with the same speed as the capstan. Moreover, the third wheel spindle and capstan spindle have the same diameter, so that during tape transport no slip occurs between the pressure roller and the two spindles.
In the event of tape stoppage the pressure roller comes to a standstill. The spindle which is in contact with the pressure roller, however, is still driven by the gear-wheel which is disposed on the capstan and therefore performs an unwinding movement on the circumference of the pressure roller. By means of suitable elastic means the spindle is constantly held in engagement with the pressure roller. As the spindle rolls over the circumference of the pressure roller, the movement characteristic of the situation of tape stoppage is obtained, namely a tilting movement of the bracket around the spindle of the idler wheel. The tilting movement is transmitted to an unlatching lever which at one end is pivotably connected to a latching member, which consists of a latching slide. On the capstan near the flywheel an unlatching cam is provided. Because of the tilting movement the free end of the unlatching lever is brought within the range of the cam, so that the flywheel will hit the free end thereof. The force which is thus exerted on the unlatching lever by the flywheel is transmitted to the latching member by the lever, so that said member is unlatched. In this known device the unlatching lever thus both has the function of a movable frame plate, which is moved by the tape-stoppage detection device during tape stoppage, and of a force-transmitting member, for unlatching the latching slide against the spring load.
A drawback of the known tape recorder is that the latching slide is unlatched abruptly and with an impact. This means that momentarily great forces are exerted on the components of the stop device. Moreover, the impact increases the number of annoying switching noises. The nature of the stop device described further demands a certain amount of mounting space in the vicinity of the pressure roller and the capstan. Such space is not always available, in which cases the described stop device cannot be used. A further drawback is that the stop device does not respond to stoppage of the take-up reel in those cases in which the supply reel is not yet completely empty. Such a situation may for example occur in the case of a cassette which does not function entirely correctly because of blocking of the take-up reel. As the tape-stoppage detection device cannot detect such a situation, unwinding of the tape continues, thus giving rise to looping of the tape in the cassette.